Commit 32cd7468 authored by Al Viro's avatar Al Viro
Browse files

link_path_walk: kill the recursion 



absolutely straightforward now - the only variables we need to preserve
across the recursive call are name, link and cookie, and recursion depth
is limited (and can is equal to nd->depth).  So arrange an array of
triples to hold instances of those and be done with that.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent bdf6cbf1

fs/namei.c

+29 −11
Original line number Diff line number Diff line
@@ -1711,8 +1711,14 @@ static inline u64 hash_name(const char *name) 
 */

static int link_path_walk(const char *name, struct nameidata *nd)

{

	struct saved {

		struct path link;

		void *cookie;

		const char *name;

	} stack[MAX_NESTED_LINKS], *last = stack + nd->depth - 1;

	int err;



start:

	while (*name=='/')

		name++;

	if (!*name)
@@ -1776,8 +1782,6 @@ Walked: 
			goto Err;



		if (err) {

			struct path link;

			void *cookie;

			const char *s;



			if (unlikely(current->link_count >= MAX_NESTED_LINKS)) {
@@ -1790,22 +1794,25 @@ Walked: 


			nd->depth++;

			current->link_count++;

			last++;



			link = nd->link;

			s = get_link(&link, nd, &cookie);

			last->link = nd->link;

			s = get_link(&last->link, nd, &last->cookie);



			if (unlikely(IS_ERR(s))) {

				err = PTR_ERR(s);

				current->link_count--;

				nd->depth--;

				last--;

				goto Err;

			}

			err = 0;

			if (unlikely(!s)) {

				/* jumped */

				put_link(nd, &link, cookie);

				put_link(nd, &last->link, last->cookie);

				current->link_count--;

				nd->depth--;

				last--;

			} else {

				if (*s == '/') {

					if (!nd->root.mnt)
@@ -1816,17 +1823,24 @@ Walked: 
					nd->flags |= LOOKUP_JUMPED;

				}

				nd->inode = nd->path.dentry->d_inode;

				err = link_path_walk(s, nd);

				last->name = name;

				name = s;

				goto start;



back:

				name = last->name;

				if (unlikely(err)) {

					put_link(nd, &link, cookie);

					put_link(nd, &last->link, last->cookie);

					current->link_count--;

					nd->depth--;

					last--;

					goto Err;

				} else {

					err = walk_component(nd, LOOKUP_FOLLOW);

					put_link(nd, &link, cookie);

					put_link(nd, &last->link, last->cookie);

					current->link_count--;

					nd->depth--;

					last--;

					goto Walked;

				}

			}
@@ -1838,9 +1852,13 @@ Walked: 
	}

	terminate_walk(nd);

Err:

	if (likely(!nd->depth))

		return err;

	goto back;

OK:

	if (likely(!nd->depth))

		return 0;

	goto back;

}



static int path_init(int dfd, const struct filename *name, unsigned int flags,

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